This disclosure relates to security in an integrated circuit device, particularly during power-up.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it may be understood that these statements are to be read in this light, and not as admissions of prior art.
Integrated circuits are powered using power supply voltages. The power supply voltages may be supplied from an external source or may be derived from an external source using on-chip circuitry. When a power supply voltage that is provided to the integrated circuit is powered up, the integrated circuit is reset into a known state. The reset of the integrated circuit may be performed by a power-on-reset (POR) signal generated by a POR circuit. The POR signal is active during the POR phase of the initialization before the configuration stage where the user information is loaded into the integrated circuit.
Some integrated circuits include a test POR input pin used for testing how changes in the power supply affect the performance of the integrated circuit. In many cases, the POR signal is generated depending on the power supply voltage value. Thus, when the power supply voltage goes below a certain threshold voltage level, this may force the integrated circuit to go through a new POR sequence. To test the response of the integrated circuit to the fluctuations in power supply voltage, the test POR input overrides the POR signal to avoid the initialization of a new POR sequence when the power supply voltage falls below the threshold voltage level. However, such testing may pose a threat to the reliability and security of the integrated circuit. This is because the testing may potentially enable someone that uses the test POR input to override the operations of the POR circuit.